"""
Terminal emulator widget.
Shows intput and output text. Allows to enter commands. Supports history.
"""
import cgi
from PyQt4.QtCore import pyqtSignal
from PyQt4.QtGui import QColor, QKeySequence, QLineEdit, QPalette, \
QSizePolicy, QTextCursor, QTextEdit, \
QVBoxLayout, QWidget
class _ExpandableTextEdit(QTextEdit):
"""
Class implements edit line, which expands themselves automatically
"""
historyNext = pyqtSignal()
historyPrev = pyqtSignal()
def __init__(self, termWidget, *args):
QTextEdit.__init__(self, *args)
self.setStyleSheet("font: 9pt \"Courier\";")
self._fittedHeight = 1
self.textChanged.connect(self._fit_to_document)
self._fit_to_document()
self._termWidget = termWidget
def sizeHint(self):
"""
QWidget sizeHint impelemtation
"""
hint = QTextEdit.sizeHint(self)
hint.setHeight(self._fittedHeight)
return hint
def _fit_to_document(self):
"""
Update widget height to fit all text
"""
documentSize = self.document().size().toSize()
self._fittedHeight = documentSize.height() + (self.height() - self.viewport().height())
self.setMaximumHeight(self._fittedHeight)
self.updateGeometry();
def keyPressEvent(self, event):
"""
Catch keyboard events. Process Enter, Up, Down
"""
if event.matches(QKeySequence.InsertParagraphSeparator):
text = self.toPlainText()
if self._termWidget.is_command_complete(text):
self._termWidget.exec_current_command()
return
elif event.matches(QKeySequence.MoveToNextLine):
text = self.toPlainText()
cursorPos = self.textCursor().position()
textBeforeEnd = text[cursorPos:]
# if len(textBeforeEnd.splitlines()) <= 1:
if len(textBeforeEnd.split('\n')) <= 1:
self.historyNext.emit()
return
elif event.matches(QKeySequence.MoveToPreviousLine):
text = self.toPlainText()
cursorPos = self.textCursor().position()
textBeforeStart = text[:cursorPos]
# lineCount = len(textBeforeStart.splitlines())
lineCount = len(textBeforeStart.split('\n'))
if len(textBeforeStart) > 0 and \
(textBeforeStart[-1] == '\n' or textBeforeStart[-1] == '\r'):
lineCount += 1
if lineCount <= 1:
self.historyPrev.emit()
return
elif event.matches(QKeySequence.MoveToNextPage) or \
event.matches(QKeySequence.MoveToPreviousPage):
return self._termWidget.browser().keyPressEvent(event)
QTextEdit.keyPressEvent(self, event)
class TermWidget(QWidget):
"""
Widget wich represents terminal. It only displays text and allows to enter text.
All highlevel logic should be implemented by client classes
User pressed Enter. Client class should decide, if command must be executed or user may continue edit it
"""
def __init__(self, *args):
QWidget.__init__(self, *args)
self._browser = QTextEdit(self)
self._browser.setStyleSheet("font: 9pt \"Courier\";")
self._browser.setReadOnly(True)
self._browser.document().setDefaultStyleSheet(self._browser.document().defaultStyleSheet() +
"span {white-space:pre;}")
self._edit = _ExpandableTextEdit(self, self)
self._edit.historyNext.connect(self._on_history_next)
self._edit.historyPrev.connect(self._on_history_prev)
self.setFocusProxy(self._edit)
layout = QVBoxLayout(self)
layout.setSpacing(0)
layout.setContentsMargins(0, 0, 0, 0)
layout.addWidget(self._browser)
layout.addWidget(self._edit)
self._history = [''] # current empty line
self._historyIndex = 0
self._edit.setFocus()
def _append_to_browser(self, style, text):
"""
Convert text to HTML for inserting it to browser
"""
assert style in ('in', 'out', 'err')
text = cgi.escape(text)
text = text.replace('\n', '
')
if style != 'out':
def_bg = self._browser.palette().color(QPalette.Base)
h, s, v, a = def_bg.getHsvF()
if style == 'in':
if v > 0.5: # white background
v = v - (v / 8) # make darker
else:
v = v + ((1 - v) / 4) # make ligher
else: # err
if v < 0.5:
v = v + ((1 - v) / 4) # make ligher
if h == -1: # make red
h = 0
s = .4
else:
h = h + ((1 - h) * 0.5) # make more red
bg = QColor.fromHsvF(h, s, v).name()
text = '%s' % (str(bg), text)
else:
text = '%s' % text # without span
is ignored!!!
scrollbar = self._browser.verticalScrollBar()
old_value = scrollbar.value()
scrollattheend = old_value == scrollbar.maximum()
self._browser.moveCursor(QTextCursor.End)
self._browser.insertHtml(text)
"""TODO When user enters second line to the input, and input is resized, scrollbar changes its positon
and stops moving. As quick fix of this problem, now we always scroll down when add new text.
To fix it correctly, srcoll to the bottom, if before intput has been resized,
scrollbar was in the bottom, and remove next lien
"""
scrollattheend = True
if scrollattheend:
scrollbar.setValue(scrollbar.maximum())
else:
scrollbar.setValue(old_value)
def exec_current_command(self):
"""
Save current command in the history. Append it to the log. Clear edit line
Reimplement in the child classes to actually execute command
"""
text = str(self._edit.toPlainText())
self._append_to_browser('in', '> ' + text + '\n')
if len(self._history) < 2 or\
self._history[-2] != text: # don't insert duplicating items
if text[-1] == '\n':
self._history.insert(-1, text[:-1])
else:
self._history.insert(-1, text)
self._historyIndex = len(self._history) - 1
self._history[-1] = ''
self._edit.clear()
if not text[-1] == '\n':
text += '\n'
self.child_exec_command(text)
def child_exec_command(self, text):
"""
Reimplement in the child classes
"""
pass
def add_line_break_to_input(self):
self._edit.textCursor().insertText('\n')
def append_output(self, text):
"""Appent text to output widget
"""
self._append_to_browser('out', text)
def append_error(self, text):
"""Appent error text to output widget. Text is drawn with red background
"""
self._append_to_browser('err', text)
def is_command_complete(self, text):
"""
Executed by _ExpandableTextEdit. Reimplement this function in the child classes.
"""
return True
def browser(self):
return self._browser
def _on_history_next(self):
"""
Down pressed, show next item from the history
"""
if (self._historyIndex + 1) < len(self._history):
self._historyIndex += 1
self._edit.setPlainText(self._history[self._historyIndex])
self._edit.moveCursor(QTextCursor.End)
def _on_history_prev(self):
"""
Up pressed, show previous item from the history
"""
if self._historyIndex > 0:
if self._historyIndex == (len(self._history) - 1):
self._history[-1] = self._edit.toPlainText()
self._historyIndex -= 1
self._edit.setPlainText(self._history[self._historyIndex])
self._edit.moveCursor(QTextCursor.End)